f08 THE Mi:CHANICAL FUNCTIONS. 



without organization, but endowed with the single 

 attribute of voluntary motion : and even this pro- 

 perty was denied to them by some authors. 



All these fanciful dreams have been dispelled by 

 the important discoveries of Ehrenberg,* who has 

 recently found that even the Manas termo is pos- 

 sessed of internal cavities for the reception and the 

 digestion of its food ; and who has rendered it pro- 

 bable that their organization is not much less com- 

 plex than that of the larger species of infusoria, in 

 which he has succeeded in tracing a muscular, a 

 nervous, and even a vascular system. 



Those animalcules, whose form can be at all dis- 

 tinguished, exhibit a great diversity of shapes, and 

 variety of modes of progressive motion. Many, as 

 the Cyclidkan, have the appearance of a thin oval 

 pellicle, smoothly gliding in all directions through 



* His first researches on the structure and classification of infu- 

 soria were published at Berlin in the year 1830, in the Abhandlan- 

 gen dcr Kouiglichen Akademie der Wissenschaften zu Berlin, for 

 the year 1830. His last great work, in folio, accompanied by an 

 atlas of 64 coloured plates, recently pubhshed, is entitled, Die 

 InfusionsthiercheH als Vollkommene Organismen, ein blick ein das 

 tic/ere organische Icben der Natur. Von D. Christian Gottfried. 

 Ehrenberg zu Berlin. Leipsig. 1838. Ehrenberg divides the 

 Infusoria into the two following classes, namely, 1. Polygastrica, 

 characterized by the possession of numerous stomachs, into which 

 the food passes from the mouth, which is single and surrounded by 

 vibrating ciHa ; and by having generally from one to four organs of 

 a bright red colour, which are supposed to be eyes. 2. Rotatoria, 

 which have ciliated organs of a circular form, creating by their 

 vibrations rotatory currents in the surrounding fluid: one longitu- 

 dinal, and several transverse vessels ; bands of muscular fibres ; a 

 distinct nervous system, with eyes, generally of a red colour; and 

 well defined organs for digestion, consisting of a moutli, jaws, gene- 

 rally furnished with teeth for mastication, an intestinal tube, with 

 pouches or dilatations corresponding to stomachs, or caeca. 



